The Jupiter engine was designed at the British firm Cosmos Engineering Co. in 1919. After the dissolution of Cosmos, it was put into production at the Bristol works in 1921. It was produced under British licence in France, Italy, Poland, Japan, and the USSR. The French Gnome–Rhône works began production of Jupiter engines in 1923.
| Configuration | 9-cylinder radial |
| Cooling | air |
| Compression ratio | 5.3 |
| Displacement | 28.7 l |
| Weight | 350 kg |
| Maximum power | 480 hp at 2000 rpm |
| Rated power | 420 hp at 1750 rpm |
